Instrument for high temperatures.



o. SIEBERT 61 A. Ktf N. INSTRUMENT FOR HIGH TEMPERATURES.

APPLICATION FILED DEG-16. 1909.

1,005,339. Patented 001. 10,1911.

of Germany,

OF CASSEL, GERMANY.

. INSTRUMENT FOR HIGH TEMPERATURES.

To all whom it may concern:

Be it known that we, CARL SIEBERT and ALBERT KIJ'HN, both citizens of the Empire residing at Cassel, in the Empire of Germany, have invented a new and useful Instrument for High Temperatures, of which the following is a specification.

Our invention relates to physical and chemical instruments for diversified purposes, which are required to withstand very high temperatures, more particularly to thermometers.

The manufacture of glass, thermometers for high temperatures is rendered impossible for. the reason that the best glass known commences to melt at a temperature of 575 centigrade, while thermometers made from quartz-glass are too expensive for general use, since it is most diflicult to obtain transparent quartz-glass. Opaque quartz-glass is certainly comparatively cheaper, but is unfit for thermometers and similar instruments for obvious reasons.

the bottom 4 part of the tu scale 0. The intermediate port on d of the Our invention relates to an improvement in the manufacture of instruments, more particularly thermometers, from quartzglass, whereby th said disadvantages are avoided. V

The improvement consists in making only those parts of the instrument, which require transparent, from transparent quartzglass, while the other parts are made from opaque quartz-glass.

We Will now proceed to describe our invention with reference to the accompanying drawing, which illustrates in a longltudinal section a thermometer embodying our invention.

In the drawing: 0 denotes a capillary thermometer tube of any known design made from transparent quartz glass and containing mercury. ThlS thermometer tube is adapted to be contained in a casing B, which comprises an upper portion 6 of transparent quartz glass, a bottom portion e, also of transparent uartz glass and an intermediatertion of opaque quartz glass.

6 bulb of the thermometer is fused in ortion e of the casing B, while the wide tube rt-ion b envelops the upper o and contains within it a Specification of Letters Patent. Application filed December 16,

Patented Oct. 10, 1911.

1909. Serial No. 533,377;

casing B is fused to the portions 6 and 6, thus forming a solidcasing for the thermometer proper. By this arrangement it is possible to produce such thermometers, of a very great length, from quartz glass at a comparatively low price. The casing may be made up of opaque quartz glass wherever it is not necessary that the mercury in the thermometer be visible-for readings.

In assembling the apparatus, the quartz glass tube a, adapted toreceive mercury or other thermometric fluid, is first inserted in I the assembled portions 12 and d of the outer casing, the upper portion of the former being left open, and the bulb of the tube a fused to the lower portion e of thecasing B which is subsequently fused to the portion 03.

Anyknown process of filling the thermome-' ter bulb and portion of the stem with a desired amount of mercury, may be used, after which the top portion of the tube a is connected to a nitrogen filler apparatus. 4 The nitrogen is then brought into the tube under a pressure of 30 atmospheres and then the upper end of the capillary tube is closed hermetically by the application of heat. The nitrogen must be placed in the tube above the mercury in order to provide the necessary from the top portion of the tube in order that such portion may be closed by heat without vaporizing the mercury. When desired, that air WhlCh may have entered the tube during application of the nitrogen filler apparatus to the tube may be removed by suction. When the thermometer proper is within the casing the top may be capped by acupola-shaped piece or by any desired capping means.

We claim:

1. A thermometer comprising a capillary thermometer tube with bulb of transparent 2. A thermometer comprising a pressure thereupon to retain it thermometer tube with bulb of transparent case and the said bulb of said capillary therquartz-glass, a scale tube enveloping the mometer tube.

upper part of said capillary thermometer CARL T tube and made of transparent quartz-glass, ALBERTKt-IHN a tubular ease of opaque quartz-glass enveloping the intermediate part of said capil- Witnesses: I lary thermometer tube, and a quartz-glass JULIUBSWILKES VET WITTELSJ portion fused to and connecting said tubular ADOLF .HAMPE. 

